1) Field of the Invention
The present invention relates to a technique for performing personal authentication using biometric information such as fingerprint, palm print, palm shape, blood vessel pattern (digital vein, palmvein, etc.), iris, and/or face image.
2) Description of the Related Art
In recent years, biometric authentication (personal authentication), which utilizes human biometric information such as fingerprint, palm print, palm shape, blood vessel pattern (digital vein, palmvein, etc.), iris, and/or face image, has been widely used for login to personal computers (PCs), entrance/exit management, etc.
Minutia matching method or pattern matching method has conventionally been used widely as a technique for verifying such biometric information.
Minutia matching method uses the position and/or direction of a fingerprint minutia, the relationship between fingerprint minutiae, etc. to perform authentication, specifically including, for example, a technique using the connection relationship between minutiae (refer to Patent Document 1 below) and a technique using the number of ridges between minutiae (refer to Patent Document 2 below).
On the other hand, pattern matching method uses encoding information based on the image information or shape of a fingerprint, or encoding information based on the frequency analysis thereof to perform authentication, and for which various kinds of techniques have also been proposed (refer to Patent Documents 3 and 4 below, for example).
Meanwhile, as a common characteristic among various minutia matching methods, authentication (verification) using a minutia matching method shows a high verification rate and thereby a short verification time to have the advantage that it is suited for one-to-many verification, while the disadvantage that it is not good at authenticating unclear images.
On the other hand, as a common characteristic among various pattern matching methods, authentication (verification) using a pattern matching method has the advantage that it is good at authenticating unclear images, while shows a low verification rate and thereby a long verification time to have the disadvantage that it is not suited for one-to-many verification.
Hence, it can be considered that authentication using verification results of both minutia matching method and pattern matching method allows for unfailing authentication even for unclear images, which are difficult to be authenticated (i.e., not supported) by a minutia matching method, whereby it is possible to decrease unsupported ratio and to improve authentication accuracy. This case, however, requires verification using both methods and thereby takes a long verification time.                [Patent Document 1]        
Japanese Patent Laid-Open No. HEI 11-195119                [Patent Document 2]        
Japanese Patent Laid-Open No. SHO 56-24675                [Patent Document 3]        
Japanese Patent Laid-Open No. HEI 6-60167                [Patent Document 4]        
Japanese Patent Laid-Open No. HEI 10-105704